Flood Maps

The Federal Emergency Management Agency (FEMA) is responsible for developing and issuing flood maps on a national level. These are the official maps for the Town on Winchester on which FEMA has delineated the special flood hazard areas (SPHA) and other applicable risk zones.

Special Flood Hazard Area

The SFHA is the area subject to flooding by the 1% annual chance flood (100-year flood); it is the area where the National Flood Insurance Policy’s (NFIP’s) floodplain management regulations must be enforced. FEMA also refers to the 100-year flood as the “base flood”, with the “base flood elevation” (BFE) defining the elevation to which flood waters will rise during the 100-year flood event. The maps also delineate the 500-year floodplain (2% annual chance flood), as well as the floodway, which is defined as the channel of a stream plus any adjacent floodplain areas that must be kept free of encroachment so that the 1% annual chance flood can be carried without substantial increases in flood heights.

Insurance Study & Rate Maps

FEMA developed a new Flood Insurance Study (FIS) and issued new Flood Insurance Rate Maps (FIRMs) for Middlesex County, including the Town of Winchester, on June 6, 2010. These new maps replaced the previous maps, which dated back to 1980. The new FIRMs can be viewed in the Engineering Department (basement level of Town Hall), at the reference desk at the town library, or by going online to the FEMA Map Service Center website. The Winchester Engineering Department can assist you in determining whether your property is located in a flood hazard area. We can also help you in determining whether an elevation certificate is available for you property.

A portion of the FIRM for the Town of Winchester is shown to the right. A general map of the 100-year and 500-year floodplains is available here.

Purpose of a FIRM

FIRMs are used by lending institutions to determine if a home is located within the 100-year floodplain and if the homeowner will need to carry flood insurance when they obtain a mortgage or refinance their home.